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排序方式: 共有97条查询结果,搜索用时 265 毫秒
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Anjana Devkota Stefano Dall'Acqua Stefano Comai Gabbriella Innocenti Pramod Kumar Jha 《Biochemical Systematics and Ecology》2010
Centella asiatica (L.) Urban is widely used in traditional medicine in many countries and in the formulation of drugs and cosmetics, and is therefore suitable as a trade item for the development of medicinal plants for the population of Nepal. The aim of this work was to select plant populations of C. asiatica with high contents of secondary metabolites growing in various localities in Nepal, and to enhance knowledge of the cultivation of this plant. Quali-quantitative analysis of bioactive triterpenes (asiaticoside and asiatic acid) and phenol derivatives (flavonoids and caffeoyl esters) was performed by HPLC-DAD-ELSD. The highest quantities of triterpenes and phenols were found in samples from the Gorkha and Chitwan districts. Regarding cultivated plants, soil fertilisation is critical, since over-rich soils affect secondary metabolite content. Plants growing in sand-rich soils produce more terpenes. This work provides indications on how to select high-terpene producing germplasm and recommendations for plant cultivation. 相似文献
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Tavares CD O'Brien JP Abramczyk O Devkota AK Shores KS Ferguson SB Kaoud TS Warthaka M Marshall KD Keller KM Zhang Y Brodbelt JS Ozpolat B Dalby KN 《Biochemistry》2012,51(11):2232-2245
Eukaryotic elongation factor 2 kinase (eEF-2K) is an atypical protein kinase regulated by Ca(2+) and calmodulin (CaM). Its only known substrate is eukaryotic elongation factor 2 (eEF-2), whose phosphorylation by eEF-2K impedes global protein synthesis. To date, the mechanism of eEF-2K autophosphorylation has not been fully elucidated. To investigate the mechanism of autophosphorylation, human eEF-2K was coexpressed with λ-phosphatase and purified from bacteria in a three-step protocol using a CaM affinity column. Purified eEF-2K was induced to autophosphorylate by incubation with Ca(2+)/CaM in the presence of MgATP. Analyzing tryptic or chymotryptic peptides by mass spectrometry monitored the autophosphorylation over 0-180 min. The following five major autophosphorylation sites were identified: Thr-348, Thr-353, Ser-445, Ser-474, and Ser-500. In the presence of Ca(2+)/CaM, robust phosphorylation of Thr-348 occurs within seconds of addition of MgATP. Mutagenesis studies suggest that phosphorylation of Thr-348 is required for substrate (eEF-2 or a peptide substrate) phosphorylation, but not self-phosphorylation. Phosphorylation of Ser-500 lags behind the phosphorylation of Thr-348 and is associated with the Ca(2+)-independent activity of eEF-2K. Mutation of Ser-500 to Asp, but not Ala, renders eEF-2K Ca(2+)-independent. Surprisingly, this Ca(2+)-independent activity requires the presence of CaM. 相似文献
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Hari Prasad Devkota Masato Watanabe Takashi Watanabe Shoji Yahara 《Phytochemistry letters》2012,5(2):284-286
Two new α-hydroxy ketone type diarylpentanoids, diplomorphanone A, 2(S)-hydroxy-1-(4-hydroxyphenyl)-5-phenyl-1-pentanone (1) and diplomorphanone B, 2(R)-hydroxy-1,5-diphenyl-1-pentanone (2) were isolated from aerial parts of Diplomorpha canescens (Meisn.) C.A. Meyer and roots of Diplomorpha ganpi (Sieb. et Zucc.) Nakai, respectively. Nine known compounds including diarylpentanoids (3–6), phenylpropanoid derivatives (7–9), (+)-afzelechin (10) and apiosylskimmin (11) were also isolated for the first time from D. ganpi. Structures of these compounds were elucidated on the basis of spectroscopic data. 相似文献
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Henderson R Sali A Baker ML Carragher B Devkota B Downing KH Egelman EH Feng Z Frank J Grigorieff N Jiang W Ludtke SJ Medalia O Penczek PA Rosenthal PB Rossmann MG Schmid MF Schröder GF Steven AC Stokes DL Westbrook JD Wriggers W Yang H Young J Berman HM Chiu W Kleywegt GJ Lawson CL 《Structure (London, England : 1993)》2012,20(2):205-214
This Meeting Review describes the proceedings and conclusions from the inaugural meeting of the Electron Microscopy Validation Task Force organized by the Unified Data Resource for 3DEM (http://www.emdatabank.org) and held at Rutgers University in New Brunswick, NJ on September 28 and 29, 2010. At the workshop, a group of scientists involved in collecting electron microscopy data, using the data to determine three-dimensional electron microscopy (3DEM) density maps, and building molecular models into the maps explored how to assess maps, models, and other data that are deposited into the Electron Microscopy Data Bank and Protein Data Bank public data archives. The specific recommendations resulting from the workshop aim to increase the impact of 3DEM in biology and medicine. 相似文献
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Collection and Use of Wild Edible Fungi in Nepal 总被引:2,自引:0,他引:2
Morten Christensen Sanjeeb Bhattarai Shiva Devkota Helle O. Larsen 《Economic botany》2008,62(1):12-23
Collection and Use of Wild Edible Fungi in Nepal. The significance of the contribution of wild edible mushrooms to rural livelihoods is acknowledged, but remains largely
unexplored. This study investigates the collection of wild edible Nepalese fungi, which species are used, and what are the
specific characteristics of the collectors and the collection. Data were collected using 282 structured questionnaires, interviews,
and forest walks in 17 districts, environmental household accounts from 413 households in two communities, and a review of
literature. A total of 228 species of wild fungi are confirmed to be used for food, and collection is most widespread among
the high-mountain Tibeto-Nepalese ethnic groups, which collect an average of 18.1 kilograms (kg) fresh mushrooms per year
per household, with some households collecting as much as 160 kg. We found no relation between wealth status and subsistence
collection, although the commercial collectors are predominantly the poor earning up to six months of unskilled labor salary
per season. Given the limited local trade and occurrence of globally marketed species, the scope for increasing contributions
to rural livelihoods from collection of mushrooms, and risks in relation to this are briefly discussed. 相似文献
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Shi Yu Tillmann Falck Anneleen Daemen Leon-Charles Tranchevent Johan AK Suykens Bart De Moor Yves Moreau 《BMC bioinformatics》2010,11(1):309